Abstract:
The compaction and proving of granular materials during construction
is fundamentally import to airport pavement design practice. This is particularly
so in countries that make significant use of granular base courses with relatively
thin asphalt surfaces, such as Australia. The compaction of dredged sand fills,
up to 1500 mm deep is also important where airport pavements are constructed
over low bearing capacity marine clays, primarily in areas of reclaimed land. The
large 180 tonne Supercompactor for compacting sand fills is no longer available in
Australia and the 50 tonne Macro rollers for proving granular pavement layers were
downgraded from 1400 to 1000 kPa tyre pressure. Meanwhile, large commercial
aircraft have ever-increasing tyre pressures and wheel loads. This has created a challenge
in the form of a gap between roller capability and aircraft demand. The gap
is relatively minor for the compaction of deep sand fills, but the inability to theoretically
compare the effect of static rollers with that of vibrating and impact rollers
makes this difficult to quantify. The alternate is an expensive field trial to demonstrate
acceptable sand density at depths to 1500 mm. In contrast, a significant gap
exists for the proving of fine crushed rock layers used in upper base courses under
thin (60–100 mm) asphalt surfaces. This challenge requires rollers with higher tyre
pressure or significantly thicker asphalt surface courses to be adopted, both of which
are expensive.
